WO2023244178A1

WO2023244178A1 - Method of recovering electrode material

Info

Publication number: WO2023244178A1
Application number: PCT/SG2023/050425
Authority: WO
Inventors: Jun Jie Ernest TANG; Yong Sheng Rodney CHUA; Fu Xing Ivan TAN; Madhavi Srinivasan
Original assignee: Nanyang Technological University
Priority date: 2022-06-15
Filing date: 2023-06-15
Publication date: 2023-12-21

Abstract

The present disclosure provides for a method of recovering electrode material from a battery or capacitor, wherein an electrode of the battery or capacitor is exposed to a solution comprising sulphate, phosphate, nitrate and/or chloride ions. The present disclosure further provides for electrode material obtained by said method and a battery/capacitator comprising said electrode material.

Description

Method of Recovering Electrode Material

Technical Field

The present disclosure refers to a method of recovering electrode material from a battery or capacitor. The present disclosure also relates to electrode material obtained by the method, and a battery or capacitor comprising the electrode material.

Background Art

With the increasing battery production for applications in energy storage and powering of portable devices (e.g., phones, laptops, etc.) to electric vehicles, concerns have been raised over its impact on the sustainability of Earth’s resources and the environmental issues related to battery waste generated at the end of the lifecycle of batteries.

In this regard, several recycling technologies have been proposed. However, most of the processes commonly involve grinding the electrode materials together with current collectors into fine powders or using strong acids for the leaching of metal components. However, these methods encounter significant disadvantages. For example, grinding electrode materials together with current collectors is not an efficient way of recovering electrode material and complicates the process of separating current collectors from electrode material. Additionally, hydrometallurgical methods such as using strong acids for leaching are not environmentally friendly, are difficult to handle and may be hazardous to health.

Other methods of recycling include pyrometallurgical methods. However, such methods disadvantageously require high energy input due to the high temperatures required and may produce toxic gases which in turn require further treatment before releasing into the atmosphere.

There is therefore a need to provide a method of recovering electrode material from batteries or capacitors that overcomes, or at least ameliorates, one or more of the disadvantages described above.

Summary

In one aspect of the present disclosure, there is provided a method of recovering electrode material from a battery or capacitor, wherein an electrode of the battery or capacitor is exposed to a solution comprising sulphate, phosphate, nitrate and/or chloride ions.

Advantageously, the solution in the disclosed method may be non-hazardous and environmentally friendly. The solution recovers electrode material from spent batteries and/or capacitors by delaminating/dislodging electrode material from the current collectors without the use of conventional strong acids to leach metal components, and also removes the need for high energy heating processes, such as melting the batteries and/or capacitors.

The presently disclosed method may also advantageously be performed under ambient conditions which avoid harsh conditions such as highly acidic environments which can result in leaching of metal components and high temperatures to melt the battery or capacitator (smelting), which may require high levels of energy input.

Advantageously, the presently disclosed method may not require grinding the electrode materials together with the current collectors into fine powders, which reduces the risks of releasing harmful pollutants, dust or fumes into the environment. Without the need for grinding, the disclosed method may also make it easier to separate and extract electrode materials and current collectors.

Unlike pyrometallurgical methods, the presently disclosed method may also advantageously not release or emit toxic gases or fumes which can pose both health and environmental risks, thereby removing the need for pre-treatment processes before the releasing into the environment.

Further advantageously, the solution may be cost-effective, non-toxic and environmentally friendly, allowing for a safe, sustainable, and scalable solution for large-scale direct recycling of batteries or capacitors.

Also advantageously, the presently disclosed method may comprise a facile and one-step separation of current collectors from electrode material, removing the need for further extraction or post-processing (e.g., leaching or re-calcination with metal precursors) of recovered electrode materials.

In another aspect of the present disclosure, there is provided a battery or capacitor comprising the recovered electrode material disclosed herein.

In a further aspect of the present disclosure, there is provided electrode material obtained by the method disclosed herein.

Advantageously, the presently disclosed method allows for the recovered electrode material to be directly used as electrode materials for battery/capacitor applications.

Further advantageously, the direct use of the recovered electrode materials may reduce energy consumption as compared to conventional hydrometallurgical and pyrometallurgical methods and may therefore reduce the overall cost of producing new batteries and/or capacitors. Recovering and reusing electrode materials may lower the expenses associated with sourcing and processing new raw materials, rendering lower costs and higher affordability for consumers.

More advantageously, direct recycling and reuse ensures hazardous materials such as heavy metals and toxic chemicals from batteries and capacitors may prevent environmental contamination by reducing the risk of these substances entering ecosystems, groundwater, or air when improperly disposed of. In addition, direct recycling and reuse of the recovered electrode materials may help create a closed-loop system by reintroducing materials from used batteries or capacitors back into the production cycle. This promotes a circular economy approach, reducing waste and ensuring a sustainable supply of materials for future battery and capacitor production.

Definitions

Unless otherwise defined herein, scientific and technical terms used in this application shall have the meanings that are commonly understood by those of ordinary skill in the art. Generally, nomenclature used in connection with, and techniques of, chemistry described herein, are those well-known and commonly used in the art.

As used herein, the term "electrode material" refers to a material comprising either anode material, cathode material, or a mixture thereof. For example, the electrode material may comprise one or more of metal/mixed metal oxides (cathode material), metal/mixed metal phosphates (cathode material), or metal/mixed metal silicates (cathode material), carbonaceous material (such as carbon, hydrocarbons, graphite) (anode material), or silicon-based materials (anode material).

As used herein, the term “delamination” refers to the mechanical separation or detachment of electrode material from the surface of a current collector within an electrochemical system, typically in the context of energy storage devices such as batteries or capacitors. It encompasses the detachment of electrode active materials, binders, and conductive additives from the current collector's substrate. As used herein, the terms “delamination” and “dislodgement” are used interchangeably .

As used herein, the term “mixed metal” or “mixed metal material” includes any compound comprising at least two metals. By way of example, where the mixed metal material is obtained during the recycling of batteries/capacitors, the mixed metal material may comprise one or more metals that are present in said batteries/capacitors, such as those present in the electrodes (e.g. cathode and anode materials).

As used herein, the term “current collector” refers to a substrate for an electrode material able to conduct electrons. By way of example, current collector may comprise metal, metallic or conductive current collectors.

As used herein, the term “black mass” refers to a composition comprising electrode materials including electrode active materials, polymeric binder, residual current collector material, and other residual particulates. The chemical composition of black mass depends upon the chemistry of the battery/capacitor. Unless the context requires otherwise or specifically stated to the contrary, integers, steps, or elements of the invention recited herein as singular integers, steps or elements clearly encompass both singular and plural forms of the recited integers, steps or elements.

Unless specified otherwise, the terms "comprising" and "comprise", and grammatical variants thereof, are intended to represent "open" or "inclusive" language such that they include recited elements but also permit inclusion of additional, unrecited elements.

As used herein, the term "about", in the context of concentrations of components of the formulations, typically means +/- 5% of the stated value, more typically +/- 4% of the stated value, more typically +/- 3% of the stated value, more typically, +/- 2% of the stated value, even more typically +/- 1% of the stated value, and even more typically +/- 0.5% of the stated value.

Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Certain embodiments may also be described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the disclosure. This includes the generic description of the embodiments with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein.

Brief Description of Drawings

The accompanying drawings illustrate disclosed embodiments and serve to explain the principles of the disclosed embodiments. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.

Fig. l

Fig. 1 is a schematic diagram of a method of recycling of batteries and/or capacitors using the method disclosed in the present invention to obtain current collector and electrode material. The obtained electrode material can be reused in new batteries and/or capacitors.

Fig. 2

Fig. 2 is a schematic diagram showing the use of an integrated sieve system in a method of the present invention.

Fig. 3

Fig. 3 is an image showing the pH values of various sulphate solutions.

Fig. 4

Fig. 4 is a series of Raman spectra of sulphate-based solutions of the present invention.

Fig. 5a

Fig. 5a is a series of Raman spectrums of NH4-based sulphates with SDS and without SDS.

Fig. 5b

Fig. 5b is a series of Raman spectra of Al-based sulphates with SDS and without SDS.

Fig. 6

Fig. 6 is a Raman spectrum showing the Raman bands of sulphates (X_a) and phosphates (Xb) of solutions of the present invention.

Fig. 7

Fig. 7 is a series of Raman spectra of solutions in Table 2: (a) control solution without sulphates and phosphates (Solution 1); (b) control with sulphates-based solution (Solution 2); (c) control with phosphates-based solution (Solution 3); and (d) control with sulphates- and phosphates-based solution (Solution 7).

Fig. 8

Fig. 8 is a series of graphs of confocal Raman spectrum of rainwater and DI water.

Fig. 9

Fig. 9 is a bar chart showing the concentration of Cl , NO3 and SO4² anions in rainwater in parts per million (ppm). Fig. 10

Fig. 10 are photographs of electrodes after sonication using diluted H2SO4, diluted HNO3, deionized (DI) water, and rainwater (RW).

Fig. 11

Fig. 11 is a series of images of electrodes after sonication at 25 °C for 2 and 5 minutes using DI H2O, rainwater (RW), Li⁺-based solution, Na⁺-based solution, NHA-based solution, Mg²⁺-based solution, Zn²⁺-based solution, and Al³⁺-based solution.

Fig. 12

Fig. 12 is an image of two electrodes after sonication using phosphates-based and sulphates-based solutions.

Fig. 13

Fig. 13 is a series of images of electrodes after sonication for 1 minute, 4 minutes, 5 minutes and 10 minutes using different solutions comprising 0.5M sodium dodecyl sulphates (SDS). Images on the right are enlarged images of the electrodes at the respective time intervals and solutions.

Fig. 14

Fig. 14 is a series of images of electrodes in the respective solutions (1-7) after sonication at 25°C for 0 minutes, 1 minute, and 15 minutes.

Fig. 15

Fig. 15 is a series of scanning electron microscope (SEM) images of recovered electrode material.

Fig. 16

Fig. 16 is an X-ray diffraction (XRD) pattern of recovered electrode materials.

Fig. 17

Fig. 17 is a schematic diagram of an electrochemical cell configuration using recovered electrode materials as anodes.

Fig. 18

Fig. 18 is a graph showing the galvanostatic charge and discharge curves of recovered electrode materials/lithium (Li) foil at 300 mA g ¹ after (i) 1; (ii) 2; (iii) 10; and (iv) 100 cycles. Fig. 19

Fig. 19 is a graph showing the (i) charge and (ii) discharge cycles of the as-assembled half-cell based on recovered electrode material/Li foil after 100 cycles.

Fig. 20

Fig. 20 is a schematic diagram of sulphate-assisted separation of black mass from current collector by sonication.

Fig. 21

Fig. 21 is a schematic diagram of a conventional approach of recycling spent commercial batteries and/or capacitors versus the method of the present invention.

Detailed Disclosure of Drawings

Referring to Fig. 1(a), an overview of the recovery of electrode materials from spent batteries or capacitors using the method disclosed herein is illustrated. The presently disclosed method facilitates the direct recycling process through the separation of electrode materials from current collectors using the solutions of the present invention and allows for the direct use of recovered electrode materials in batteries or capacitors.

Referring to Fig. 1(b), spent batteries or capacitors are placed into a shredder where the batteries/capacitors are shredded (1) to expose internal components such as electrode materials and current collectors. The shredded batteries/capacitors are then immersed in the solutions of the present invention and sonicated (2) to facilitate delamination/ dislodgement of the electrode materials from the current collectors. The solutions of the present invention also participate in the separation of electrode materials from the current collectors via a physical separation. The separation may be assisted by the presence of ions in the solution with the possible formation of hydrogen bonds between the anions, water molecules and electrode material. The separated electrode materials suspended in the solution are then further centrifuged (3) to separate the electrode materials from the solution before drying (4) in an oven to obtain recovered electrode materials for further applications (battery fabrication). The solution may be recovered and reused and recycled (5) for recycling a second (or more) batches of batteries/capacitors.

A system for carrying out the method of the present invention is shown in Fig. 2(a). The shredded batteries/capacitors and the solutions of the present invention are contained in a primary (inner) container which is then further contained in a secondary (outer) container. The primary container comprises holes which serve as a sieve for finer particles to pass through to the secondary container. The two containers then act as a sieve system to separate particles of different sizes. The containers containing the shredded battery materials and solutions are sonicated to dislodge/ delaminate the electrode materials from the current collectors. The sonication process assists in the separation of the finer electrode materials from the current collectors, allowing the separated electrode materials to pass through the holes into the secondary container. The larger current collectors remaining are then collected directly from the primary container. The separation of the electrode materials and current collector is then accomplished by the simple and straightforward removal of the primary container from the secondary container. Fig. 2(b) further illustrates the separation process of Fig. 2(a).

Referring to Fig. 21, current approaches to recycle spent batteries and/or capacitors such as hydrometallurgy and pyrometallurgy processes comprise shredding (A) to obtain shredded batteries and/or capacitors. An additional grinding step (B) is often required to further break up all the components in the shredded batteries and/or capacitors comprising current collectors and electrode materials, to form a powdered black mass. Hydrometallurgical processes such as leaching the black mass with strong acids (C) are often used to dissolve components which are then filtered. The treated materials then require further processing (D) such as re-calcination with metal precursors of recovered electrode materials before they can be reused in the synthesis (E) of new batteries/capacitors. Unlike current approaches, the present invention may not require an additional grinding step and uses the solutions disclosed herein to separate electrode materials from current collectors directly. Furthermore, the present invention may not require post-processing and allows for the recovered electrode materials to be used directly in the synthesis of new batteries/capacitors.

Detailed Disclosure of Embodiments

The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description.

Current approaches to recycle spent batteries and/or capacitors, which include but are not limited to hydrometallurgy and pyrometallurgy, may very often require an additional grinding step to break up all the components such as current collectors and electrode materials in the shredded batteries and/or capacitors into a powdered form. A major disadvantage of such grinding step may include the intermixing of current collector materials with the electrode materials in the powdered black mass, which may be easily avoided and circumvented with the present invention. Leaching of the black mass with strong acids may further dissolve current collectors such as aluminium and copper and increase the difficulty for further processing during extraction and separation. In addition, the exposure to harsh environments (e.g. strong acids) would lead to further complications in direct recycling of the active electrode materials.

To address the challenges discussed, the inventors employed non-toxic and environmentally friendly rainwater and formulated green solutions to recycle spent commercial batteries and/or capacitors by delaminating/ dislodging electrode materials from current collectors, thereby obviating the need for strong acids and harsh conditions. Unlike conventional methods, the present invention may not require extensive post-treatment in the recovery of electrode materials for direct use in new batteries and/or capacitors.

The present invention comprises a method of recovering electrode material from a battery or capacitor using non-toxic and environmentally friendly solutions. The method may enable the physical separation of electrode materials from current collectors and may allow for the recovered electrode materials to be used directly in further applications in batteries and capacitors.

In particular, the present invention may not require an additional step of grinding the shredded batteries and/or capacitors into powdered form, allowing for the separation of current collectors from electrode materials in their original states without any chemical changes to material composition.

Furthermore, the present invention may not require further post-processing (e.g., leaching or re-calcination with lithium precursors) of the recovered electrode materials and allows for the recovered electrode materials in the form of metal/ mixed metal oxides, metal/ mixed metal phosphates and/or metal/ mixed metal silicates to be directly used as the cathode/anode materials for battery applications.

The recovered electrode material obtained by the presently disclosed method may comprise one or more metal/mixed metal oxides, metal/mixed metal phosphates, or metal/mixed metal silicates as cathode materials, and carbonaceous material (such as carbon, hydrocarbons, graphite) or silicates/silicon-based materials (such as elemental silicon (Si), silicon oxides (SiO, SiO ) and silicon- based composites (e.g. SiCF/C)) as anode materials.

The present invention relates to a method of recovering electrode material from a battery or capacitor, wherein an electrode of the battery or capacitor is exposed to a solution comprising sulphate, phosphate, nitrate and/or chloride ions.

The electrode may be an anode and/or a cathode.

The electrode material may comprise metal oxides, metal phosphates, metal silicates, mixed metal oxides, mixed metal phosphates and/or mixed metal silicates, elemental silicon, silicon oxides, carbonaceous materials, carbon, hydrocarbons and/or polymers. The metal or mixed metal is selected from the group consisting of lithium, cobalt, nickel, aluminium, manganese, chromium, iron, titanium, and combinations thereof. The electrode material may be selected from the group consisting of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese cobalt oxide, lithium titanium oxide, lithium nickel oxide, lithium manganese dioxide, lithium manganese nickel oxide, lithium nickel cobalt aluminium oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, lithium nickel phosphate, lithium cobalt phosphate and lithium manganese silicate.

Unlike conventional approaches where strong acids are used for leaching of metals, the present invention may not require such highly acidic environments. The non-toxic and environmentally friendly rainwater and formulated green solutions disclosed herein have mild pH values which are very unlikely to pose health and environmental risks.

The pH of the solution may be in the range of about 4 to about 7, from about 4 to about

6.5, from about 4 to about 6, from about 4 to about 5.5, from about 4 to about 5, from about 4 to about 4.5, from about 4.5 to about 7, from about 4.5 to about 6.5, from about 4.5 to about 6, from about 4.5 to about 5.5, from about 4.5 to about 5, from about 5 to about 7, from about 5 to about

6.5, from about 5 to about 6, from about 5 to about 5.5, from about 5.5 to about 7, from about 5.5 to about 6.5, from about 5.5 to about 6, from about 6 to about 7, from about 6 to about 6.5, from about 6.5 to about 7, or at most about 4, or at most about 4.5, or at most about 5, or at most about

5.5, at most about 6, at most about 6.5, at most about 7; or about 4, about 4.5, about 5, about 5.5, about 6, about 6.5, about 7, or any ranges or values therebetween.

The mild pH values of the solutions disclosed herein may be an inherent result of dissolving metal salts and/or ammonium salts of anions with weak acid strengths.

The solution may comprise metal salts and/or ammonium salts of sulphate, phosphate, nitrate and/or chloride, while the metal of the metal salt may be selected from the group consisting of lithium, sodium, magnesium, zinc, and aluminium.

The solution may be selected from the group consisting of:

(i) solution comprising sulphate ions;

(ii) solution comprising phosphate ions;

(iii) solution comprising sulphate and phosphate ions;

(iv) solution comprising chloride, nitrate and sulphate ions;

(v) solution comprising chloride, nitrate, and phosphate ions; and

(vi) solution comprising chloride, nitrate, sulphate, and phosphate ions.

In addition, the solution may comprise sulphate, phosphate, chloride, and nitrate anions in different concentrations with respect to one another. Specifically, the solution may be selected from the group consisting of:

(i) solution comprising sulphate ions;

(ii) solution comprising phosphate ions;

(iii) solution comprising sulphate and phosphate ions in a ratio of about 2:8 to about 8:2;

(iv) solution A comprising chloride and nitrate ions, and solution B comprising sulphate, wherein the ratio of chloride to nitrate is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution B is in the range of about 2:8 to about 8:2;

(v) solution A comprising chloride and nitrate ions, and solution C comprising phosphate, wherein the ratio of chloride to nitrate is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution C is in the range of about 2:8 to about 8:2; and

(vi) solution A comprising chloride and nitrate ions, solution B comprising sulphate, and solution C comprising phosphate, wherein the ratio of chloride to nitrate is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution B to solution C is in the range of about (2 to 4):(2 to 4):(2 to 4).

The solution of the present invention may comprise sulphate and phosphate ions in a ratio of about 2:8 to about 8:2, about 2:8 to about 7:3, about 2:8 to about 6:4, about 2:8 to about 5:5, about 2:8 to about 4:6, about 2:8 to about 3:7, about 3:7 to about 8:2, about 3:7 to about 7:3, about 3:7 to about 6:4, about 3:7 to about 5:5, about 3:7 to about 4:6, about 4:6 to about 8:2, about 4:6 to about 7:3, about 4:6 to about 6:4, about 4:6 to about 5:5, about 5:5 to about 8:2, about 5:5 to about 7:3, about 5:5 to about 6:4, about 6:4 to about 8:2, about 6:4 to about 7:3, about 7:3 to about 8:2, or any ranges or values therebetween.

The solution may comprise solution A and solution B, wherein solution A comprises chloride and nitrate ions, and wherein solution B comprises sulphate ions. In such embodiments, the ratio of chloride to nitrate ions in solution A is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution B is in the range of about 2:8 to about 8:2.

In some embodiments, the ratio of chloride to nitrate ions in solution A is in the range of about 2:8 to about 8:2, about 2:8 to about 7:3, about 2:8 to about 6:4, about 2:8 to about 5:5, about 2:8 to about 4:6, about 2:8 to about 3:7, about 3:7 to about 8:2, about 3:7 to about 7:3, about 3:7 to about 6:4, about 3:7 to about 5:5, about 3:7 to about 4:6, about 4:6 to about 8:2, about 4:6 to about 7:3, about 4:6 to about 6:4, about 4:6 to about 5:5, about 5:5 to about 8:2, about 5:5 to about 7:3, about 5:5 to about 6:4, about 6:4 to about 8:2, about 6:4 to about 7:3, about 7:3 to about 8:2, or any ranges or values therebetween.

In some embodiments, the ratio of solution A to solution B is in the range of about 2:8 to about 8:2, about 2:8 to about 7:3, about 2:8 to about 6:4, about 2:8 to about 5:5, about 2:8 to about 4:6, about 2:8 to about 3:7, about 3:7 to about 8:2, about 3:7 to about 7:3, about 3:7 to about 6:4, about 3:7 to about 5:5, about 3:7 to about 4:6, about 4:6 to about 8:2, about 4:6 to about 7:3, about 4:6 to about 6:4, about 4:6 to about 5:5, about 5:5 to about 8:2, about 5:5 to about 7:3, about 5:5 to about 6:4, about 6:4 to about 8:2, about 6:4 to about 7:3, about 7:3 to about 8:2, or any ranges or values therebetween.

The solution of the present invention may comprise solution A and solution C, wherein solution A comprises chloride and nitrate ions, and wherein solution C comprises phosphate ions. In such embodiments, the ratio of chloride to nitrate ions in solution A is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution C is in the range of about 2:8 to about 8:2.

The ratio of chloride to nitrate ions in solution A may be in the range of about 2:8 to about 8:2, about 2:8 to about 7:3, about 2:8 to about 6:4, about 2:8 to about 5:5, about 2:8 to about 4:6, about 2:8 to about 3:7, about 3:7 to about 8:2, about 3:7 to about 7:3, about 3:7 to about 6:4, about 3:7 to about 5:5, about 3:7 to about 4:6, about 4:6 to about 8:2, about 4:6 to about 7:3, about 4:6 to about 6:4, about 4:6 to about 5:5, about 5:5 to about 8:2, about 5:5 to about 7:3, about 5:5 to about 6:4, about 6:4 to about 8:2, about 6:4 to about 7:3, about 7:3 to about 8:2, or any ranges or values therebetween.

The ratio of solution A to solution C may be in the range of about 2:8 to about 8:2, about 2:8 to about 7:3, about 2:8 to about 6:4, about 2:8 to about 5:5, about 2:8 to about 4:6, about 2:8 to about 3:7, about 3:7 to about 8:2, about 3:7 to about 7:3, about 3:7 to about 6:4, about 3:7 to about 5:5, about 3:7 to about 4:6, about 4:6 to about 8:2, about 4:6 to about 7:3, about 4:6 to about 6:4, about 4:6 to about 5:5, about 5:5 to about 8:2, about 5:5 to about 7:3, about 5:5 to about 6:4, about 6:4 to about 8:2, about 6:4 to about 7:3, about 7:3 to about 8:2, or any ranges or values therebetween.

The solution may comprise solution A, solution B and solution C, wherein solution A comprises chloride and nitrate ions, solution B comprises sulphate ions, and solution C comprises phosphate ions. In such embodiments, the ratio of chloride to nitrate ions in solution A is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution B to solution C is in the range of about (2 to 4): (2 to 4): (2 to 4).

The ratio of solution A to solution B to solution C may be in the range of about 2:2:2 (1:1:1), about 2:2:3, about 2:2:4, about 2:3:2, about 2:3:3, about 2:3:4, about 2:4:2, about 2:4:3, about 2:4:4, about 3:2:2, about 3:2:3, about 3:2:4, about 3:3:2, about 3:3:4, about 3:4:2, about 3:4:3, about 3:4:4, about 4:2:2, about 4:2:3, about 4:2:4, about 4:3:2, about 4:3:3, about 4:3:4, about 4:4:2, about 4:4:3, or any ranges or values therebetween.

More specifically, the concentration of sulphate, phosphate, nitrate and/or chloride ions in the solution may be about 0.3 M to about 2 M, about 0.3 M to about 1.5 M, about 0.3 M to about 1 M, about 0.3 M to about 0.75 M, about 0.3 M to about 0.6 M, about 0.3 M to about 0.5 M, about 0.3 M to about 0.4 M, about 0.4 M to about 2 M, about 0.4 M to about 1.5 M, about 0.4 M to about 1 M, about 0.4 M to about 0.75 M, about 0.4 M to about 0.6 M, about 0.4 M to about 0.5 M, about 0.5 M to about 2 M, about 0.5 M to about 1.5 M, about 0.5 M to about 1 M, about 0.5 M to about 0.75 M, about 0.5 M to about 0.6 M, about 0.6 M to about 2 M, about 0.6 M to about 1.5 M, about 0.6 M to about 1 M, about 0.6 M to about 0.75 M, about 0.75 M to about 2 M, about 0.75 M to about 1.5 M, about 0.75 M to about 1 M, about 1 M to about 2 M, about 1 M to about 1.5 M, about 1.5 M to about 2 M, about 1 M to about 1.5 M, or any ranges or values therebetween.

Besides the extraction of the electrode materials, it is of great importance that other materials, such as current collectors, are to be recovered are in their original states without degradation, loss of mass or change in chemical composition in the method disclosed herein. In the presence of certain additives, the quality of the other recovered materials may be enhanced when used with the method disclosed herein. Additives may include surfactants which can reduce degradation of the structural integrity in the recovered materials during the separation process.

Specifically, the solution may further comprise a sulphate-containing surfactant.

The surfactant may be selected from a group consisting of ammonium lauryl sulphate, sodium laureth sulphate, sodium myreth sulphate, sodium pareth sulphate, ammonium laureth sulphate, sodium lauryl sulphate, and sodium dodecyl sulphate (SDS).

The concentration of sulphate ions in the surfactant may be about 0.01 M to about 0.85 M, about 0.01 M to about 0.8 M, about 0.01 M to about 0.75 M, about 0.01 M to about 0.7 M, about 0.01 M to about 0.65 M, about 0.01 M to about 0.6 M, about 0.01 M to about 0.55 M, about 0.01 M to about 0.5 M, about 0.01 M to about 0.45 M, about 0.01 M to about 0.4 M, about 0.01 M to about 0.35 M, about 0.01 M to about 0.3 M, about 0.01 M to about 0.25 M, about 0.01 M to about 0.2 M, about 0.01 M to about 0.15 M, about 0.01 M to about 0.1 M, about 0.01 M to about 0.05 M, about 0.05 M to about 0.85 M, about 0.05 M to about 0.8 M, about 0.05 M to about 0.75 M, about 0.05 M to about 0.7 M, about 0.05 M to about 0.65 M, about 0.05 M to about 0.6 M, about 0.05 M to about 0.55 M, about 0.05 M to about 0.5 M, about 0.05 M to about 0.45 M, about 0.05 M to about 0.4 M, about 0.05 M to about 0.35 M, about 0.05 M to about 0.3 M, about 0.05 M to about 0.25 M, about 0.05 M to about 0.2 M, about 0.05 M to about 0.15 M, about 0.05 M to about 0.1 M, about 0.1 M to about 0.85 M, about 0.1 M to about 0.8 M, about 0.1 M to about 0.75 M, about 0.1 M to about 0.7 M, about 0.1 M to about 0.65 M, about 0.1 M to about 0.6 M, about 0.1 M to about 0.55 M, about 0.1 M to about 0.5 M, about 0.1 M to about 0.45 M, about 0.1 M to about 0.4 M, about 0.1 M to about 0.35 M, about 0.1 M to about 0.3 M, about 0.1 M to about 0.25 M, about 0.1 M to about 0.2 M, about 0.1 M to about 0.15 M, about 0.15 M to about 0.85 M, about 0.15 M to about 0.8 M, about 0.15 M to about 0.75 M, about 0.15 M to about 0.7 M, about 0.15 M to about 0.65 M, about 0.15 M to about 0.6 M, about 0.15 M to about 0.55 M, about 0.15 M to about 0.5 M, about 0.15 M to about 0.45 M, about 0.15 M to about 0.4 M, about 0.15 M to about 0.35 M, about 0.15 M to about 0.3 M, about 0.15 M to about 0.25 M, about 0.15 M to about 0.2 M, about 0.2 M to about 0.85 M, about 0.2 M to about 0.8 M, about 0.2 M to about 0.75 M, about 0.2 M to about 0.7 M, about 0.2 M to about 0.65 M, about 0.2 M to about 0.6 M, about 0.2 M to about 0.55 M, about 0.2 M to about 0.5 M, about 0.2 M to about 0.45 M, about 0.2 M to about 0.4 M, about 0.2 M to about 0.35 M, about 0.2 M to about 0.3 M, about 0.2 M to about 0.25 M, about 0.25 M to about 0.85 M, about 0.25 M to about 0.8 M, about 0.25 M to about 0.75 M, about 0.25 M to about 0.7 M, about 0.25 M to about 0.65 M, about 0.25 M to about 0.6 M, about 0.25 M to about 0.55 M, about 0.25 M to about 0.5 M, about 0.25 M to about 0.45 M, about 0.25 M to about 0.4 M, about 0.25 M to about 0.35 M, about 0.25 M to about 0.3 M, about 0.3 M to about 0.85 M, about 0.3 M to about 0.8 M, about 0.3 M to about 0.75 M, about 0.3 M to about 0.7 M, about 0.3 M to about 0.65 M, about 0.3 M to about 0.6 M, about 0.3 M to about 0.55 M, about 0.3 M to about 0.5 M, about 0.3 M to about 0.45 M, about 0.3 M to about 0.4 M, about 0.3 M to about 0.35 M, about 0.35 M to about 0.85 M, about 0.35 M to about 0.8 M, about 0.35 M to about 0.75 M, about 0.35 M to about 0.7 M, about 0.35 M to about 0.65 M, about 0.35 M to about 0.6 M, about 0.35 M to about 0.55 M, about 0.35 M to about 0.5 M, about 0.35 M to about 0.45 M, about 0.35 M to about 0.4 M, about 0.4 M to about 0.85 M, about 0.4 M to about 0.8 M, about 0.4 M to about 0.75 M, about 0.4 M to about 0.7 M, about 0.4 M to about 0.65 M, about 0.4 M to about 0.6 M, about 0.4 M to about 0.55 M, about 0.4 M to about 0.5 M, about 0.4 M to about 0.45 M, about 0.45 M to about 0.85 M, about 0.45 M to about 0.8 M, about 0.45 M to about 0.75 M, about 0.45 M to about 0.7 M, about 0.45 M to about 0.65 M, about 0.45 M to about 0.6 M, about 0.45 M to about 0.55 M, about 0.45 M to about 0.5 M, about 0.5 M to about 0.85 M, about 0.5 M to about 0.8 M, about 0.5 M to about 0.75 M, about 0.5 M to about 0.7 M, about 0.5 M to about 0.65 M, about 0.5 M to about 0.6 M, about 0.5 M to about 0.55 M, about 0.55 M to about 0.85 M, about 0.55 M to about 0.8 M, about 0.55 M to about 0.75 M, about 0.55 M to about 0.7 M, about 0.55 M to about 0.65 M, about 0.55 M to about 0.6 M, about 0.6 M to about 0.85 M, about 0.6 M to about 0.8 M, about 0.6 M to about 0.75 M, about 0.6 M to about 0.7 M, about 0.6 M to about 0.65 M, about 0.65 M to about 0.85 M, about 0.65 M to about 0.8 M, about 0.65 M to about 0.75 M, about 0.65 M to about 0.7 M, about 0.7 M to about 0.85 M, about 0.7 M to about 0.8 M, about 0.7 M to about 0.75 M, about 0.75 M to about 0.85 M, about 0.75 M to about 0.8 M, about 0.8 M to about 0.85 M, or any ranges or values therebetween.

In addition to the recovery of electrode materials, the method disclosed herein may further comprise recovering current collectors, which may comprise copper, aluminium, nickel, titanium, platinum, zinc, stainless steel, carbonaceous materials, and carbon. Carbonaceous materials may comprise carbon-fibres, carbon wires and carbon cloth.

Besides the addition of surfactants, the method may further comprise agitating the solution. The agitation may comprise stirring, shaking, bubbling, recirculating or sonicating the solution.

Unlike the high temperatures required in the conventional pyrometallurgic methods, the method disclosed herein may not require heating or elevated temperatures and may be performed at room temperatures.

The temperature of the solution before agitation/sonication may be in a range of at least about 10 °C, at least about 15 °C, at least about 20 °C, at least about 23 °C, at least about 25 °C, at least about 30 °C, at least about 40 °C, at least about 50 °C; or from about 10 °C to about 50 °C, from about 10 °C to about 40 °C, from about 10 °C to about 30 °C, from about 10 °C to about 25 °C, from about 10 °C to about 23 °C, from about 10 °C to about 20 °C, from about 10 °C to about 15 °C, from about 15 °C to about 50 °C, from about 15 °C to about 40 °C, from about 15 °C to about 30 °C, from about 15 °C to about 25 °C, from about 15 °C to about 23 °C, from about 15 °C to about 20 °C, from about 20 °C to about 50 °C, from about 20 °C to about 40 °C, from about 20 °C to about 30 °C, from about 20 °C to about 25 °C, from about 20 °C to about 23 °C, from about 23 °C to about 50 °C, from about 23 °C to about 40 °C, from about 23 °C to about 30 °C, from about 23 °C to about 25 °C, from about 25 °C to about 50 °C, from about 25 °C to about 40 °C, from about 25 °C to about 30 °C, from about 30 °C to about 50 °C, from about 30 °C to about 40 °C, from about 40 °C to about 50 °C, or at most about 10 °C, or at most about 15 °C, or at most about 20 °C, or at most about 23 °C, at most about 25 °C, at most about 30 °C, at most about 40 °C, at most about 50 °C; or about 10 °C, about 15 °C, about 20 °C, about 23 °C, about 25 °C, about 30 °C, about 40 °C, about 50 °C, or any ranges or values therebetween. In a preferred embodiment, the sonication is performed with the temperature of the solution at 23 °C. Agitation/sonication of solutions may cause a rise in temperature in liquids due to different processes such as adiabatic heating, molecular friction, energy dissipation within the liquid, and localized heating caused by cavitation. Hence, the rise in temperature of the solution after agitation/sonication is an expected phenomenon.

The temperature of the solution after agitation/sonication is at a range of at least about 10 °C, at least about 15 °C, at least about 20 °C, at least about 23 °C, at least about 25 °C, at least about 30 °C, at least about 40 °C, at least about 50 °C; least about 60 °C, at least about 70 °C, at least about 80 °C, at least about 90 °C; or from about 10 °C to about 90 °C, from about 10 °C to about 80 °C, from about 10 °C to about 70 °C, from about 10 °C to about 60 °C, from about 10 °C to about 50 °C, from about 10 °C to about 40 °C, from about 10 °C to about 30 °C, from about 10 °C to about 25 °C, from about 10 °C to about 23 °C, from about 10 °C to about 20 °C, from about 10 °C to about 15 °C, from about 15 °C to about 90 °C, from about 15 °C to about 80 °C, from about 15 °C to about 70 °C, from about 15 °C to about 60 °C, from about 15 °C to about 50 °C, from about 15 °C to about 40 °C, from about 15 °C to about 30 °C, from about 15 °C to about 25 °C, from about 15 °C to about 23 °C, from about 15 °C to about 20 °C, from about 20 °C to about 90 °C, from about 20 °C to about 80 °C, from about 20 °C to about 70 °C, from about 20 °C to about 60 °C, from about 20 °C to about 50 °C, from about 20 °C to about 40 °C, from about 20 °C to about 30 °C, from about 20 °C to about 25 °C, from about 20 °C to about 23 °C, from about 23 °C to about 90 °C, from about 23 °C to about 80 °C, from about 23 °C to about 70 °C, from about 23 °C to about 60 °C, from about 23 °C to about 50 °C, from about 23 °C to about 40 °C, from about 23 °C to about 30 °C, from about 23 °C to about 25 °C, from about 25 °C to about 90 °C, from about 25 °C to about 80 °C, from about 25 °C to about 70 °C, from about 25 °C to about 60 °C, from about 25 °C to about 50 °C, from about 25 °C to about 40 °C, from about 25 °C to about 30 °C, from about 30 °C to about 90 °C, from about 30 °C to about 80 °C, from about 30 °C to about 70 °C, from about 30 °C to about 60 °C, from about 30 °C to about 50 °C, from about 30 °C to about 40 °C, from about 40 °C to about 90 °C, from about 40 °C to about 80 °C, from about 40 °C to about 70 °C, from about 40 °C to about 60 °C, from about 40 °C to about 50 °C, from about 50 °C to about 90 °C, from about 50 °C to about 80 °C, from about 50 °C to about 70 °C, from about 50 °C to about 60 °C, from about 60 °C to about 90 °C, from about 60 °C to about 80 °C, from about 60 °C to about 70 °C, from about 70 °C to about 90 °C, from about 70 °C to about 80 °C, from about 80 °C to about 90 °C, or at most about 10 °C, or at most about 15 °C, or at most about 20 °C, or at most about 23 °C, at most about 25 °C, at most about 30 °C, at most about 40 °C, at most about 50 °C, at most about 60 °C, at most about 70 °C, at most about 80 °C, at most about 90 °C; or about 10 °C, about 15 °C, about 20 °C, about 23 °C, about 25 °C, about 30 °C, about 40 °C, about 50 °C, about 60 °C, about 70 °C, about 80 °C, about 90 °C, or any ranges or values therebetween. Unlike the conventional use of strong acids which can cause leaching of metal ions into the acid solutions, the solution disclosed herein may not comprise metal ions leached from the batteries and/or capacitors. The solution may not contain dissolved metal ions from the batteries and/or capacitors and may remain in their original states without changes in their chemical compositions.

The present invention discloses a physical separation of the recovered electrode material from the current collectors without dissolution of metals, metal oxides, metal phosphates, metal silicates, mixed metal oxides, mixed metal phosphates and/or mixed metal silicates from the batteries and/or capacitors into the solution. The separation may be assisted by the presence of sulphates with the possible formation of hydrogen bonds between the anions, water molecules and the black mass (Fig. 20). The separation may also be further assisted by the presence of bubbles (cavitation) in the solutions shown in Fig. 20.

The present invention also discloses a battery or capacitor comprising the recovered electrode material disclosed herein.

The present invention also discloses an electrode material obtained by the method disclosed herein.

The recovered electrode material may be used in cathode and/or anode applications. For cathode applications, the recovered electrode material may be regenerated as a cathode by reacting with lithium precursors. For anode applications, the recovered electrode material may be used as an anode by mixing the recovered electrode materials with carbon and binders on metal foils.

The process of directly using recovered electrode material in new batteries/capacitors may allow for a sustainable approach towards battery /capacitor manufacturing, and the recovery and reintegration of the recovered electrode materials offer several advantages as follow below.

Firstly, the process helps reduce the environmental impact associated with battery production. By reusing electrode materials, the need for mining and extracting new resources is minimized, leading to a decrease in energy consumption and greenhouse gas emissions. Additionally, it helps mitigate the disposal of potentially hazardous materials from spent batteries, reducing the risk of soil and water contamination.

Secondly, utilizing recovered electrode materials promotes resource efficiency. Many battery components, such as lithium, cobalt, nickel, and other metals, are finite resources that are costly to extract and refine. By recycling these materials from used batteries, valuable resources are conserved and can be reintroduced into the production cycle.

Once the recovered electrode materials are deemed suitable for reuse, they can be integrated into the manufacturing of new batteries. These materials may be combined with newly sourced components to create hybrid electrode structures, optimizing the performance and longevity of the battery cells. The reintegration of recovered materials may occur in various battery chemistries, including lithium-ion, nickel-metal hydride, or even emerging technologies like solid- state batteries.

The battery or capacitor comprising the recovered electrode material obtained from the method disclosed herein may have high galvanostatic charge and discharge capacities with stable electrochemical performance even after multiple cycles, showcasing that the present invention may offer great potential and advantages in reducing the environmental footprint and dependence on raw materials. This would allow for a more sustainable and circular approach within the battery /capacitor industry, supporting the transition towards a greener and more resource -efficient future.

Examples

Non-limiting examples of the invention will be further described in greater detail by reference to specific Examples, which should not be construed as in any way limiting the scope of the invention.

Example 1: Procedure for Preparing Solutions

Example la: Single Salt Sulphate-based Solutions

Example la(i): 0.5M Monovalent cationic (Li⁺/Na⁺/NH4⁺) sulphate solutions

0.1 mol of monovalent cationic sulphate salt (Li2SO4 or Na2SO4 or (NH4)2SO4) was dissolved in 0.2kg of DI water and stirred to ensure all the salts have been dissolved to form a homogenous 0.5M sulphate solution.

Example la(ii): 0.5M Divalent cationic (Mg²⁺/Zn²⁺) sulphate solutions

0.1 mol of divalent cationic sulphate salt (MgSC or ZnSO4) was dissolved in 0.2kg of DI water and stirred to ensure all the salts have been dissolved to form a homogenous 0.5M sulphate solution. Example la(iii): 0.5M Trivalent cationic (Al³⁺) sulphate solution

0.1 mol of trivalent cationic sulphate salt (Ah SO^s) was dissolved in 0.6kg of DI water and stirred to ensure all the salts have been dissolved to form a homogenous 0.5M sulphate solution.

Example lb: Sulphate -based Solutions with Surfactant

Example lb(i): 0.5M Sodium dodecyl sulphate (SDS) solution [Table 1, Solution II

0.1 mol of SDS was dissolved in 0.2kg of DI water and stirred to ensure all the salts have been dissolved to form a homogenous 0.5M sulphate solution.

Example lb(ii): 0.5M Mixed (NH4)SO^ solution with SDS at 1:1 v/v [Table 1, Solution III

0.5M of the (NH4)2SO4 and SDS solutions prepared according to Example la(i) and la(iv) were mixed in equal volumes to form a homogenous 0.5M sulphate solution.

Example Ib(iii): 0.5M Mixed AllSo4 solution with SDS at 1:1 v/v [Table 1, Solution III1

0.5M of the Al(SO4)3 and SDS solutions prepared according to Example la(iii) and la(iv) were mixed in equal volumes to form a 0.5M homogenous sulphate solution.

Table 1. Sulphate-based solutions with sodium dodecyl sulphates (SDS)

Solution Formulation pH

I 0.5 mol kg ¹ SDS in Di H2O ~6

II (0.5 mol kg ¹ SDS in Di H₂O) + ~5

(0.5 mol kg ¹ (NH4)SCin Di H2O) at 1:1 v/v

III (0.5 mol kg ¹ SDS in Di H₂O) + ~4

(0.5 mol kg ¹ A12(SC>4)3in Di H2O) at 1:1 v/v

Example 1c: Phosphate-based Solutions

0.5M Monovalent cationic (Li⁺/Na⁺/NH4⁺) phosphate solutions

0.1 mol of monovalent cationic phosphate salt (LilDPC^ or NaH2PO4 or (NH4)H2PO4 was dissolved in 0.2kg of DI water and stirred to ensure all the salts have been dissolved to form a homogenous 0.5M phosphate solution. Example Id: Mixed Complex Salt Solutions

Example ld(i): Mixed monovalent cationic salt solution (NaCl + L1NO3+ NaNO3) [Table 2, Solution 11

0.1 mol of the individual monovalent cationic salt - NaCl, LiNO3, NaNO3 was separately dissolved in 0.2kg of DI water and stirred to ensure all the salts have been dissolved to form the respective homogenous 0.5M salt solutions. 0.5M of the respective NaCl, LiNO3, NaNO3 salt solutions were then mixed in equal volumes and stirred to ensure a homogenous mixed salt solution.

Example ld(ii): 0.5M mixed monovalent cationic sulphate solution (Li2SO4+ Na2SO4 + 2SO₄) [Table 2, Solution 21

0.5M of the respective Li2SO₄, Na2SO₄, and (NH₄)2SO₄ salt solutions prepared according to Example la(i) were mixed in equal volumes and stirred to ensure a homogenous 0.5M sulphate solution.

Example Id(iii): 0.5M mixed ammonium and sodium dihydrogen phosphate solution (NaH PO₄+ NH4H2PO4) [Table 2, Solution 31

0.1 mol of the individual monovalent cationic salt - NaPEPCC and NH4H2PO4 was separately dissolved in 0.2kg of DI water and stirred to ensure all the salts have been dissolved to form the respective homogenous 0.5M phosphate solutions. 0.5M of the respective NalEPCC and NH4H2PO4 phosphate solutions were then mixed in equal volumes and stirred to ensure a homogenous 0.5M phosphate solution.

Example ld(iv): Mixed salt solution containing sulphate and phosphate (Li SO₄+ Na2SO₄ + 2SO4 + NaH₂PO₄+ NH4H2PO4) [Table 2, Solution 41

0.5M of the respective salt solutions prepared according to Example ld(ii) and Id(iii) were mixed in equal volumes and stirred to ensure a homogenous mixed salt solution.

Example ld(v): Mixed salt solution containing sulphate (NaCl + LiNCh + NaNCh + Li2SO₄+ Na?SO4 + [Table 2, Solution 51

0.5M of the respective salt solutions prepared according to Example ld(i) and ld(ii) were mixed in equal volumes and stirred to ensure a homogenous mixed salt solution. Example ld(vi): Mixed salt solution containing phosphate (NaCl + L1NO3 + NaNO3 + NaH2PO4+

NH4H2PO4) [Table 2, Solution 61

0.5M of the respective salt solutions prepared according to Example ld(i) and Id(iii) were mixed in equal volumes and stirred to ensure a homogenous mixed salt solution.

Example Id(vii): Mixed salt solution containing sulphate and phosphate (NaCl + LiNO3 + NaNO3

+ Li₂SO₄+ Na₂SO₄ + ₂SO4 + NaH₂PO₄+ NH4H2PO4) [Table 2, Solution 71

0.5M of the respective salt solutions prepared according to Example 1 d(i)-(iii) were mixed in equal volumes and stirred to ensure a homogenous mixed salt solution.

Table 2. Mixed sulphates and/or phosphates in complex salt solutions

Solution Sulphate-, Sulphates-based Phosphates- Solution pH Remark phosphate- solution based solution mixture less solution ratio

Solution 1 (0.5M NaCl+ - - 1:0:0 5 Sulphate-, phosphate-less

0.5M LNO’, + (Control as a complex salt

0.5M NaNO’J solution) in DI water

Solution 2 - (0.5M Li2SO4+ - 0:1:0 5 Mixed sulphates-based

0.5M Na’SOr + solution

0.5M (NHO2SO4) in DI water

Solution 3 - - (0.5M Nal l’POr 0:0:1 4 Mixed phosphates-

•2H2O+ based solution

0.5M NH4H2PO4) in DI water

Solution 4 - Solution 2 Solution s 0:1:1 4 Mixed sulphates and phosphates-based solution

Solution 5 Solution 1 Solution 2 - 1:1:0 5 A mixture of complex salt solution and sulphates- based solution Solution 6 Solution 1 - Solution s 1:0:1 4 A mixture of complex salt solution and phosphates- based solution

Solution 7 Solution 1 Solution 2 Solution s 1: 1:1 4 A mixture of complex salt solution, sulphates and

Example 2: Characterization of Solutions

Example 2a: Raman Spectroscopy of Single Salt Sulphate-based Solutions

The dominant Raman bands corresponding to the different components of the solution were labelled “X”, “Y” and “Z”. The Raman band region labelled X_a corresponds to the different monovalent and multivalent cations -based sulphates components while the Raman band regions labelled Yi and Y2 correspond to the DI H2O component.

Example 2a(i): Raman Spectra of Monovalent cationic (Li⁺/Na⁺/NH4⁺) sulphate solutions (Example la(i))

The presence of a peak in the band region labelled X_a in the Raman spectra of lithium, sodium, and ammonium sulphate solutions (Fig. 4) indicated the presence the different monovalent cations-based (Li⁺/Na⁺/NH4⁺) sulphates components absent in DI water. The presence of the peaks in the Raman band regions labelled Y 1 and Y2 indicated the presence of the DI H2O component.

Example 2a(ii): Raman Spectra of Divalent cationic (Mg²⁺/Zn²⁺) sulphate solutions (Example la(iil)

The presence of a peak in the band region labelled X_a in the Raman spectra of magnesium and zinc sulphate solutions (Fig. 4) indicated the presence the different divalent cations-based (Mg²⁺/Zn²⁺) sulphates components absent in DI water. The presence of the peaks in the Raman band regions labelled Yi and Y2 indicated the presence of the DI H2O component.

Example 2a(iii): Raman Spectrum of Trivalent cationic (Al³⁺) sulphate solutions (Example la(iii))

The presence of a peak in the band region labelled X_a in the Raman spectra of aluminium sulphate solutions (Fig. 4) indicated the presence the trivalent cation-based (Al³⁺) sulphate component absent in DI water. The presence of the peaks in the Raman band regions labelled Y 1 and Y2 indicated the presence of the DI H2O component. Example 2b: Raman Spectroscopy of Sulphate-based Solutions with Surfactant

Example 2b(i): Raman Spectrum of Mixed solution with SDS at 1:1 v/v (Example

lb(ii))

The mixed (NH4)SCC solution with SDS at 1:1 v/v of Example lb(ii) was identified through the distinct Raman bands of SDS appearing in the regions labelled “Zi” and “Z2” (Fig. 5a), together with the Raman bands in regions “X_a”, “Yi” and “Y2”.

Example 2b(ii): Raman Spectrum of Mixed Al2SOb) solution with SDS at 1:1 v/v (Example Ib(iii))

The mixed A^SCbb solution with SDS at 1:1 v/v of Example la(vi) was identified through the distinct Raman bands of SDS appearing in the regions labelled “Zi” and “Z2” (Fig. 5b), together with the Raman bands in regions “X_a”, “Yi” and “Y2”.

Example 2b(iii): Raman Spectrum of powdered SDS

The characteristic Raman bands of the SDS surfactant were identified through the distinct peaks appearing in the regions labelled “Zi” and “Z2” in the Raman spectrum (Figs. 5a-5b).

Example 2c: Raman Spectroscopy of Phosphate -based Solutions

Example 2c(i): Raman Spectra of ammonium sulphate versus ammonium phosphate solution

The differences between ammonium phosphate and ammonium sulphate solutions were indicated with the distinct Raman band positions and intensity differences, with the absence of peaks X_a and the presence of peaks Xb for the ammonium phosphate solution (Fig. 6).

Example 2d: Raman Spectroscopy of Mixed Complex Salt Solutions

Example 2d(i): Raman Spectrum of mixed monovalent cationic salt solution (NaCl + LiN03+ NaNO3) (Example ld(i))

The mixed (NaCl + LiN03+ NaNO3) cationic salt control solution of Example 1 d(i) was identified through the distinct Raman bands as a control solution (Fig 7(a)). Example 2d(ii): Raman Spectrum of mixed monovalent cationic sulphate solution (L12SO4+ Na?SO4 + (NH₄)2SO₄) (Example ld(ii))

A control solution with sulphate-based solution with Example ld(ii) was identified through the Raman bands which consists of Raman bands of the control solution as well as the other Raman bands corresponding to the sulphate-based solution (Fig. 7(b)).

Example 2d(iii): Raman Spectra of ammonium and sodium dihydrogen phosphate solution (NaH₂PO₄+ NH4H2PO4) (Example Id(iii))

A control solution with phosphate-based solution with Example Id(iii) was identified through the Raman bands which consist of Raman bands of the control solution as well as the other Raman bands corresponding to the phosphate-based solution (Fig. 7(c)).

Example 2d(iv): Raman Spectra of mixed complex salt solution containing sulphate and phosphate (NaCl + LiNO₃ + NaNO₃ + Li₂SO₄+ Na₂SO₄ + (NH₄)₂SO4 + NaH₂PO₄+ NH4H2PO4) (Example Id(vii))

A control solution with sulphate-based and phosphate-based solution with Example ld(iv) was identified through the Raman bands which consist of Raman bands of the control solution as well as the other Raman bands corresponding to the sulphate- and phosphate-based solutions (Fig. 7(d)).

Example 2e: Raman Spectroscopy of Rainwater

Example 2e: Raman Spectrum of Rainwater

Confocal Raman spectroscopy results indicated that the peaks in the Raman band regions labelled Yi and Y₂ in rainwater (Fig. 8(a)) were found to be similar to the peaks in the Raman band of DI H2O (Fig. 8(b)), suggesting that rainwater and DI H₂0 have similar solution structures.

Example 2f: Anion Chromatography technique

Ion chromatography technique using Dionex ICS- 1000 Anion was employed to determine the anion species in rainwater. The concentration of anions was referenced with Dionex Seven Anion Standard Combined Standard Solution. The results indicated that the concentration of NO₃ and SO₄ ² were the dominant anion species in rainwater (Fig. 9). Anions such as fluorides and phosphates are not detected in the collected local rainwater sample. Example 2g: pH of Solutions

Using DI water and rainwater as control solutions, the formulated 0.5M sulphate-based solutions comprising Li, Na, NH4, Mg, Zn and Al cations in Example 1 were measured using pH- indicator strips and were found to be between pH 4 to 7 (Fig. 3). Di-water and rainwater were found to have a pH value of ~4. Li- and Zn- based sulphates solutions were found to have a pH value of ~5. Na-, NH4-, Mg- based sulphates solutions were found to have a pH value of ~6. Al- based sulphate solution was found to have a pH value of ~4.

Example 3: Method of Recovering Electrode Materials from Batteries/Capacitors

Example 3a: Shredding of batteries/capacitors

Spent batteries were placed into a shredder where the batteries/capacitors were physically shredded and the internal components such as electrode materials and current collectors were exposed (Fig. 1(b)).

Example 3b: Sonication and Separation

The shredded batteries/capacitors are then immersed in the solutions of Example 1 and sonicated to facilitate dislodgement/delamination of the electrode materials from the current collectors. A sieve system may be employed to facilitate the separation (Fig. 2). The sieve system consists of two containers, with a primary (inner) container having two rows of designated placement of 3 mm holes that functions as a sieve while the outer container functions as a secondary containment container (Fig. 2(a)). The containers containing the shredded battery/capacitor materials and solutions were then sonicated to dislodge/delaminate the electrode materials from the current collectors. The sonication process assists in the separation of the separated finer electrode materials from the larger current collectors, allowing the separated electrode materials to pass through the holes into the secondary . The current collectors were then collected directly from in the primary (inner) container. The separation of the recovered electrode materials and the current collectors was achieved by the simple and straightforward removal of the primary container from the secondary container.

Example 3c: Centrifugation and Drying

The separated electrode materials suspended in the solution in Example 3b were then recovered by further centrifugation and drying processes. Example 3d: Recycling of Solution

The solutions recovered in Example 3c may then be reused for a next batch of recovery as described in Examples 3b and 3c.

Example 4: Performance of Different Solutions

Example 4a: Rainwater

Rainwater was presented as an effective solution as compared to DI H2O (Fig. 10) to dislodge/ delaminate the electrode materials from the current collectors, despite both having similar solution structure based on confocal Raman spectroscopy results (Fig. 8). It was suggested that the presence of ions in the rainwater might be the key contribution factor for an ideal recycling solution. As the rainwater were known to contain nitric, sulphuric and hydrochloric acids, diluted H2SO4 and HNO3 (Fig. 10) were prepared as control samples for comparison purposes. It was noteworthy that despite the close pH readings of prepared H2SO4 (pH 2.56) and HNO3 (pH 2.83) solutions, the diluted H2SO4 solution was able to remove the electrode materials into the solution better than the diluted HNO3 solution after the sonication process. On the other hand, rainwater while having a much milder pH ~4-5 than that of diluted H2SO4 solution, demonstrated good efficiency in the removal of the electrode materials from the current collectors, highlighting the importance of sulphate anions as a critical component for an ideal recycling solution.

Example 4b: Sulphate -based Solutions

While the electrode sonicated in the DI H2O had the electrode materials remained largely intact and unseparated on the current collector (Fig. 11), in stark contrast, the electrode materials sonicated in sulphates-containing solution (e.g., rainwater or monovalent/multivalent cations - based, had the majority of their electrode materials dislodged/ delaminated from the aluminium current collector after 2 and 5 minutes of sonication at 25 °C respectively in Fig. 11.

Example 4c: Phosphate-based Solutions

The feasibility of employing phosphates -based solution for direct recycling purposes was demonstrated by preparing NH4⁺-based phosphates and sulphates -based solutions according to Examples la(i) and lc(i). Similar to the effectiveness of sulphate-based solution, the phosphate- based solution was also found to be capable of delaminating/dislodging the electrode materials effectively from the copper current collector (Fig. 12). Example 4d: Sulphate-based Solutions with sodium dodecyl sulphate (SDS)

Although the sulphates -based recycling solution was found to be effective in delaminating/dislodging the electrode materials during the sonication process, it was noted that the aluminium current collector recovered using NHA and Al³⁺ suffered from severe breakage and corrosion (Fig. 11). The breakage and corrosion were likely to be caused by the interaction between the dissolved ions and the collector during the sonication process. Such reaction resulted in additional filtration and extraction steps to separate the dislodged/delaminated active materials and broken foil pieces, and a poorer quality of the recovered Al current collector. Sodium dodecyl sulphate (SDS) was then added into the recycling solutions to overcome the issues with breakage and corrosion of the current collector.

The composite salt-based solutions based on NHA and Al³⁺ sulphates with SDS were formulated according to Table 1 (Solution II and III respectively) and in Example lb(ii)-(iii). The single salt solution based on SDS in DI H2O was prepared as a control solution (Solution I) and according to Example lb(i). As shown in Fig. 13, the electrode materials were completely removed without the breakage and corrosion of the aluminium current collector after the electrodes were sonicated in solution with SDS. On the other hand, the electrode sonicated in the control solution (Solution I) had the bulk of electrode materials intact on the aluminium collector, demonstrating the importance of composite salt-based solution for effective removal of the electrode materials from the current collector without any damage to the current collector.

Example 4e: Mixed Sulphate and/or Phosphate -based Solutions

A series of solutions (Solution 1 to 7) was prepared according to Table 2 to evaluate the effect of mixed sulphates and/or phosphates -based solution in a complex solution environment (e.g., in a mixed cations and anions environment) for the delamination of electrodes. The electrodes were placed into the respective solutions 1 to 7 in Fig. 14. Solution 1 was set as the control solution with no sulphates and phosphates anions present. The electrodes were then sonicated in the prepared solutions, with the results taken after a duration of 1 minute and 15 minutes respectively. Distinctively, in the presence of mixed sulphates and phosphates -based solution, the electrodes were effectively delaminated off the aluminium current collector as compared to the electrode in the control solution after 15 minutes (Fig. 14). Furthermore, no corrosion of the recovered aluminium foil (current collector) was observed when sonicated in the solution with mixed sulphates and/or phosphate system. Example 5: Recovered Electrode Materials

Example 5a: Characterization

The elemental composition and crystal structure of the recovered electrode materials were characterized using a scanning electron microscope (SEM) coupled with electron dispersive X-ray spectrometer (EDS) (JEOL FESEM 7600F) and X-ray diffractometer (Bruker D8 Advance), respectively. Match! software was used to analyze the X-ray diffraction pattern based on inorganic crystal structure database (ICSD). Based on the SEM -EDS measurement, the elemental compositions of Ni, Co, Al, O, and C were detected (Fig. 15). From the X-ray diffraction pattern of the recycled materials, a composite of lithium cobalt nickel aluminium oxides and carbon-based materials (carbon and graphite) were identified (Fig. 16).

Example 5b: Application of Recovered Electrode Materials

The feasibility of the recovered materials was tested for anode applications. Prototypes in the form of a coin cell were assembled and electrochemically tested. A slurry was prepared by mixing the recycled materials with conductive carbon black and polyvinylidene fluoride (PVDF) binder in a weight ratio of 8: 1 : 1. The slurry was then cast onto a copper foil using a doctor blade, followed by the overnight vacuum drying process. A half-cell configuration (Fig. 17) was assembled to test the electrode (active mass~2 mg) as the anode (working electrode) with 16 mm lithium foil as counter and reference electrode. A monolayer polypropylene (Celgard 2400) was employed as a separator while the 1 M LiPFe in ethylene carbonate (EC): ethyl methyl carbonate (EMC) 3:7 v/v was used as the electrolyte. The coin cell was then assembled in a glovebox under an inert argon environment. The half-cell was electrochemically cycled between the range of 0.005 V to 2.5 V at a current density of 300 mA g \ with a rest time of 1 minute in between steps.

The galvanostatic charge and discharge curves of the recovered materials/Li cell are shown in Fig. 18. Remarkably, the direct application of recovered electrode materials as the anode delivered a high discharge capacity of 446.4 mAh g ¹ in the initial cycle at a current density of 300 mA g^-1. Moreover, the cell also exhibited a stable electrochemical performance with a discharge capacity of -138.1 mAh g ¹ after 100 cycles (Fig. 19). Industrial Applicability

The present invention relates to a method of recovering electrode material from a battery or a capacitor, wherein an electrode of the battery or capacitor is exposed to a solution comprising sulphate, phosphate, nitrate and/or chloride ions. The solution in the method disclosed herein is environmentally friendly and non-hazardous, which obviates the need for conventional strong acids used in leaching or high energy input for pyrometallurgical means, and may not require extensive post-treatment steps to recover electrode materials . Furthermore, the disclosed method of recovering electrode material from a battery or a capacitor may be cost-effective, simple, environmentally friendly, and scalable in the manufacturing process for mass production.

It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within the scope of the appended claims.

Claims

CLAIMS A method of recovering electrode material from a battery or capacitor, wherein an electrode of the battery or capacitor is exposed to a solution comprising sulphate, phosphate, nitrate and/or chloride ions. The method of claim 1, wherein the electrode material comprises metal oxides, metal phosphates, metal silicates, mixed metal oxides, mixed metal phosphates, mixed metal silicates, elemental silicon, silicon oxides, carbonaceous materials, carbon, hydrocarbons and/or polymers. The method of claim 2, wherein the metal or mixed metal is selected from the group consisting of lithium, cobalt, nickel, aluminium, manganese, chromium, iron, titanium, and combinations thereof. The method of any one of claims 1 to 3, wherein the electrode material is selected from the group consisting of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese cobalt oxide, lithium titanium oxide, lithium nickel oxide, lithium manganese dioxide, lithium manganese nickel oxide, lithium nickel cobalt aluminium oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, lithium nickel phosphate, lithium cobalt phosphate and lithium manganese silicate. The method of any one of claims 1 to 4, wherein the pH of the solution is in the range of about 4 to about 7. The method of any one of claims 1 to 5, wherein the solution comprises metal salts and/or ammonium salts of sulphate, phosphate, nitrate and/or chloride. The method of claim 6, wherein the metal of the metal salt is selected from the group consisting of lithium, sodium, magnesium, zinc, and aluminium. The method of any one of claims 1 to 7, wherein the solution is selected from the group selected consisting of:

(i) solution comprising sulphate ions;

(ii) solution comprising phosphate ions;

(iii) solution comprising sulphate and phosphate ions;

(iv) solution comprising chloride, nitrate and sulphate ions;

(v) solution comprising chloride, nitrate, and phosphate ions; and

(vi) solution comprising chloride, nitrate, sulphate, and phosphate ions. The method of any one of claims 1 to 8, wherein the solution is selected from the group consisting of:

(i) solution comprising sulphate ions;

(ii) solution comprising phosphate ions;

(vi) solution A comprising chloride and nitrate ions, solution B comprising sulphate, and solution C comprising phosphate, wherein the ratio of chloride to nitrate is in the range of about 2:8 to about 8:2, and the ratio of solution A to solution B to solution C is in the range of about (2 to 4):(2 to 4):(2 to 4). The method of any one of claims 1 to 9, wherein the solution is selected from the group selected consisting of:

(i) solution comprising sulphate ions;

(ii) solution comprising phosphate ions;

(iii) solution comprising sulphate and phosphate ions in a ratio of about 1:1;

(iv) solution A comprising chloride and nitrate ions, and solution B comprising sulphate, wherein the ratio of chloride to nitrate is in the range of about 1:1;

(v) solution A comprising chloride and nitrate ions, and solution C comprising phosphate, wherein the ratio of chloride to nitrate is in the range of about 1:1, and the ratio of solution A to solution C is in the range of about 1:1; and

(vi) solution A comprising chloride and nitrate ions, solution B comprising sulphate, and solution C comprising phosphate, wherein the ratio of chloride to nitrate is in the range of about 1:1, and the ratio of solution A to solution B to solution C is in the range of about 1:1:1. The method of any one of claims 1 to 10, wherein the concentration of sulphate, phosphate, nitrate and/or chloride ions is about 0.3 M to about 2 M. The method of any one of claims 1 to 11, wherein the solution further comprises a sulphate - containing surfactant. The method of claim 12, wherein the surfactant is selected from a group consisting of ammonium lauryl sulphate, sodium laureth sulphate, sodium myreth sulphate, sodium pareth sulphate, ammonium laureth sulphate, sodium lauryl sulphate, and sodium dodecyl sulphate (SDS). The method of claims 12 or 13, wherein the concentration of sulphate ions in surfactant is about 0.01 M to about 0.85 M. The method of any one of claims 1 to 14, wherein the method further comprises recovering current collector. The method of any one of claims 1 to 15, wherein the current collector comprises copper, aluminium, nickel, titanium, stainless steel, carbonaceous materials, and carbon. The method of any one of claims 1 to 16, wherein the method further comprises agitating the solution. The method of claim 17, wherein the temperature of the solution before agitation is about 20 °C to about 40 °C. The method of claim 17, wherein the temperature of the solution during and/or after agitation is about 20 °C to about 80 °C. The method of any one of claims 1 to 19, wherein the solution does not comprise metal ions leached from the batteries and/or capacitors. A battery or capacitor comprising the recovered electrode material of any one of claims 1 to 20. Electrode material obtained by the method of any one of claims 1-20.